TPIC44L01, TPIC44L02, TPIC44L03

4-CHANNEL SERIAL AND PARALLEL LOW-SIDE PRE-FET DRIVER

9

POST OFFICE BOX 655303

PRINCIPLES OF OPERATION

serial data operation

The TPIC44L01, TPIC44L02, and TPIC44L03 offer serial input interface to the microcontroller to transfer control

data to the predriver and fault data back to the controller. The serial input interface consists of:

– Chip select

Serial data is shifted into the least significant bit (LSB) of the SDI shift register on the rising edge of the first SCLK

after CS has transitioned from 1 to 0. Four clock cycles are required to shift the first bit from the LSB to the most

significant bit (MSB) of the shift register. Four clock cycles must occur before CS transitions high for proper

control of the outputs. Less than four clock cycles result in fault data being latched into the output control buffer.

Eight bits of data can be shifted into the device, but the first 4 bits shifted out are always the fault data and the

last 4 bits shifted in are always the output control data. A low-to-high transition on CS latches the contents of

the serial shift register into the output control register. A logic 0 input to SDI turns the corresponding parallel

output off and a logic 1 input turns the output on (see Figure 12).

GATE3 ON

GATE2 ON

GATE1 OFF

GATE0 OFF

12

3

4

Present Output Data

New Data

3-State

FLT3

FLT2

FLT1

FLT0

IN3

3-State

SCLK

CS

SDI

New Data

Output Control

Register Data

SDO

(a) 4-Bit Serial Word Example

Figure 12